The present invention relates to a barrier material which is impervious to water.
Nonwoven webs currently are employed in a variety of such disposable absorbent products as diapers; incontinent products; feminine care products, such as tampons and sanitary napkins; wipes; towels; sterilization wraps; medical drapes, such as surgical drapes and related items; medical garments, such as hospital gowns, shoe covers, and the like, to name but a few. The nonwoven webs can be utilized as a single layer or as a component of a multilayered laminate or composite. When a multilayered laminate or composite is present, often each layer is a nonwoven web. Such structures are useful for wipes, towels, industrial garments, medical garments, medical drapes, and the like.
Desired characteristics of such nonwoven webs frequently include permeability to air and water vapor (breathability), but impermeability to liquids. Perhaps the most common product exhibiting these characteristics is a laminate of three nonwoven webs, the outer layers being spunbonded webs and the inner layer being a meltblown web. Such a material is referred to in the art as an SMS laminate. The webs of which the laminate is composed typically are prepared from polyolefins, with polypropylene being the polymer of choice. While these laminates and similar materials have found wide-spread acceptance, there still is an opportunity for materials having an increased impermeability to water. For example, SMS laminates are porous in order to provide the desired breathability. However, liquids can penetrate through the fabric under certain circumstances, such as when the liquid is under pressure or pressure is applied to fabric to which liquid has been applied. While the inclusion of a film in the laminate will prevent passage of liquid, breathability can be either lost or significantly reduced.